Air conditioning apparatus



March 23, 1954 J. DITZLER ET AL 2,672,734

AIR CONDITIONING APPARATUS Filed Nov. 7, 1950 6 Sheets-Sheet l l I l lINVEIV 0185 Jae? 4,. DMZ/m and Gerald .4, ef 8/ M01 0.

March 1954 J. L. DITZLER ET AL AIR CONDITIONING APPARATUS 6 Sheets-Sheet2 Filed Nov. 7, 1950 JziL...

March 23, 1954 J. L. DITZLER ET AL 2,672,734

AIR CONDITIONING APPARATUS Filed Nov. 7, 1950 6 Sheets-Sheet 3 aEVHPORFIT R L EoNosNSE/i @I a f; 8W 5J+I L h i 1% 4 )J r F F |& s v 5 i5I 8 5 i r' N T T March 1954 J. DITZLER ET AL AIR CONDITIONING APPARATUSFiled Noy. 7, 1950 6 Sheets-Sheet 4 25 60 F/GG March 23, 1954 J. L.DITZLER ET AL 2,672,734

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Ma ATTORNEY March 23, 1954 J. DITZLER ET AL 2,672,734 AIR CONDITIONINGAPPARATUS Filed Nov. 7, 1950 6 Sheets-Sheet 6 INDOOR 4 44 16 45005751?INDOOR Oumooa All? FHN HIR FAN HEHTEIQ HIE HEHT LINE

Dar-000k 73 2mm INVENTORfi' John 1..- Oiaz/gr and, BY Gerald 4,. 8/5 1 MU. g ve v Patented Mar. 23, 1954 2,672,734 AIR CONDITIONING APPARATUSJohn L. Ditzler, Sharon,

Mass., assi and Gerald L. Biehn,

gnors to Westinghouse Electric Corporation, East Pittsburgh, Pa., acorporation of Pennsylvania Application November 7, 1950,

3 Claims.

This invention relates to refrigeration apparatus, and relates moreparticularly to heat pumps of the type used for air cooling in summerand for air heating in winter.

Prior heat pumps for cooling air in summer and for heating air in winterhave been unduly complicated and costly, and have required elaboratecontrols for reversal of operation. This invention overcomes thesedisadvantages.

A feature of this invention is that the evaporator and condenser arearranged to have an Another feature of this invention is that the tubesused as evaporator tubes in summer are supported directly over the tubesused at that time as condenser tubes, and precipitate moisture condensedfrom the air thereon for providing evaporative cooling thereof.

Another feature of this invention is rate fans are used to move air indifferent directions, thereby enabling them to be connected to ductsextending in different directions.

Another feature of this invention is that simple, effective controlsystems may be used, which energize electric heaters for auxiliaryindoor heat when needed, and which defrost or prevent the frosting ofthe evaporator tubes in the heating season.

Another feature of this invention is that the heat exchange tubes arecentrally arranged in supporting racks with spaces on both sides thereoffor the location of electric heaters and filters so that the air flowcan be in either direction without affecting performance.

Another feature of this invention is that the refrigerant paths are soarranged that the air flow through the heat exchange tubes can be ineither direction without affecting efiiciency.

Another feature of this invention is that in case of failure of anycomponent, the reversing Serial No. 194,400

valve means used will operate in the heating cycle, preventing anypossibility of the heat pump operating in the cooling cycle during theheating season.

An object of the invention is to simplify heat pumps used for heatingair in winter and for cooling air in summer.

Another object of the invention is to simplify the controls of heatpumps used for heating air in winter and for cooling air in summer.

Another object of the invention is to improve the performance of heatpumps for heating air in winter and for cooling air in summer.

The invention will now be described with reference to the drawing, ofwhich:

Fig. 1 is a side elevation of a heat pump embodying this invention;

Fig. 2 is an end elevation of the heat pump;

Fig. 3 is a simplified flow diagram illustrating the refrigerant circuitin the heating cycle;

Fig. 4 is a simplified flow diagram illustrating the refrigerant circuitin the cooling cycle;

Fig. 5 is an enlarged side elevation, partially in the heating cycle;

Fig. 6 is an enlarged side elevation of the piston of the valve means;

Fig. 7 is a sectional view along the lines l-'! of Fig. 5, with arrowsillustrating the flow of the refrigerant in the heating cycle;

Fig. 8 is a view similar to Fig 7 and illustrates the flow of therefrigerant in control circuit which may be Fig. 10 is a diagrammaticview illustrating another control circuit which may be used.

The hermetically sealed, refrigerant compressor i0 is supported by theresilient supports H on the base channels l2 and between the verticalchannels l3.

The finned heat exchanger M which acts as the condenser for thecompressor in the cooling cycle, is supported from the channels l3directly above the compressor, and the finned heat exchanger l5 whichacts as the evaporator during the cooling cycle, is supported from thechannels I3 directly above the heat exchanger [4. The slits IS in thecross support I! between the heat exchangers l4 and I5 permit moisturecondensed from the air during the cooling cycle on the surface of theheat exchanger I5, to drain upon the heat exchanger I4'so as to aid incooling it by evaporative cooling.

. then over the coil through and at The suction and discharge pipes l8and i9 respectively, of the compressor are connected to the reversingvalve means and through same to the heat exchangers l4 and 15. Thecontrol for the reversing valve means consists of the three-way valve 2|operated by the solenoid 22, and connected by the tube 23 to thedischarge side of the compressor, by the tube 24 to the suction side ofthe compressor, and by the tube 25 to the space above the piston in thereversing valve 20.

The heat exchanger l4 comprises the three coils 2B, 21 and 28 (Figs. 3and 4), which are connected at one side through the capillary tubes 30,3| and 32 respectively, to the three coils 34, 35 and 36 of the heatexchanger IS. The capillary tubes contain the strainers 40. The heatexchangers l4 and I5 are connected at their other sides through thepipes 42 and 43 respectively, to the reversing valve 20.

The evaporator and condenser are seen to have an equal number ofrefrigerant paths, the expansion of the refrigerant taking place in eachpath, through its individual capillary tube, in-

stead of through the usual expansion valves,

which will not permit reverse flow, and which when used in a reversecycle system, have to have check valves and by-pass pipes, and which aremuch slower acting than the capillary tubes. The capacity of the heatpumps may varying the number of paths. Each path may, for example,provide one ton of refrigeration effect.

The air flows over the coils of each heat exchanger in parallel. Figs. 3and 4 of the drawing, the outdoor air flows first over the coil 26, thenover the coil 21 and 28. The indoor air flows first over the coil 34,then over the coil 35, and then over the coil 36. Thus air flow could bereversed when required by duct locations without afiecting theperformance of the heat exchangers.

Since the capillary tubes interconnecting the heat exchangers arewrapped around the suction pipe, they add superheat to the the same timethe liquid in the ca illary tubes is sub-cooled.

The filter I63 is arranged across the inlet to the heat exchanger l5,and the indoor air and booster electric heaters 44 and 45 respectively,are arranged across its outlet. The electric outdoor air heater 46 isarranged across the inlet of the heat exchanger l4, and the screen 41 isarranged across the inlet to the heater 46.

Using the control ing, the booster heater 45 and the outdoor air heater46 are not used.

The heat exchangers l4 and i5 are centrally located between the channelsl3, with space on opposite sides thereof for the electric heaters, andin the case of the heat exchanger I5, for the air filter. This permitsthe electric heaters and the filter to be properly placed for air floweither direction.

The centrifugal fan 48 driven by the electric motor 49 draws outdoor airthrough the screen 41, the electric heater 46 and the heat exchanger I4,and then discharges this air back to outdoors, this flow being in thesame direction in both the heating and cooling cycles.

The centrifugal fan 50 driven by the electric motor 5| recirculatesindoor air through the heat exchanger l5 and the electric in the samedirection in both heating cycles.

be varied by Thus, with reference to gas passing theresystem of Fig. 9of the draw- 50 are contained in the racks 9 which are bolted to thechannels l3, and may be so connected to the channels that their outletsand inlets may be reversed or so that they discharge vertically insteadof horizontally.

The reversing valve 20 (Figs. 5-8) comprises the cylinder wall 52providing a cylinder in which is slidably positioned the piston 53. Thecoil spring 54 is between the bottom of the piston and the base 55 ofthe valve and opposes down movement of the piston. The base is securedto the cylinder wall by the machine screws 55.

The removable head 51 of the valve is secured to its cylinder wall bythe machine screws 58, and has the aligning pin 59 attached thereto andwhich extends slidably into the piston for preventing its rotation. Thehead has an inlet opening in its center in which is threaded thecoupling 60 to which the tube 25 (Fig. l) is connected. 1

The cylinder wall has connected thereinto intermediate its ends, thepipes 43, I8, 42 and IS. The piston 53 has the lower slot Ed thereinwhich lines up with the inner ends of the pipes 42 and I9 when, duringthe heating cycle, the piston is in its normal upper positionillustrated by Figs. 5 and '7, permitting fluid to flow through thesepipes in the direction indicated by the arrows of Fig. '7. The pistonalso has the'lower slot (55 which lines up at this time with the pipes43 and I8 permitting fluid flow through these pipes in the directionindicated by the arrows of Fig. '7.

The piston has the upper slots 66 and 61 which extend at right angles tothe slots 64 and 65. The slot 66 lines up with the pipes 43 and I8 when,during the cooling cycle, the piston is depressed under the pressure ofthe fluid admitted by the solenoid controlled valve 2! (Fig. 1), andpermits fluid to flow through these pipes in the direction indicated bythe arrows of Fig. 8. At this time the slot 61 lines up with the pipesl8 and 42 permitting fluid to flow through these pipes in the directionindicated by the arrows of Fig. 8.

Operation-Fig. 9

In the operation of the heat pump using the control scheme illustratedby Fig. 9 of the drawing, the operator by placing the switch 1|} on itsfirst contact 1| closes the circuit energizing the indoor air fan 50from the electric line. Placing the switch on its second contact 12closes a circuit connecting the relays 13 line, to the other side ofwhich the indoor thermostat 15 is connected. If the thermostat is inmiddle position only, the indoor air fan operates and providesventilation without either heating or cooling.

If the thermostat calls for cooling at, for example, '18 F. it willtouch the contact 16 completing the energizing circuit of the relay 13,causing it to pull up its armatures 11 and 18. The armature 11 willstrike the contact 19 and connect the solenoid 22 across the line,causing it to be energized and to admit gas from the compressor l0 intothe reversing valve means 20, causing the piston 53 to be depressed andto route the fluid flow as illustrated by Figs. 3 and 8. At

The fans 48 and the same time the armature 18 will strike the heaters-44and 45 p the cooling and I I sure cut-out 88 of the compressor 10'.

contact and will close the energizing circuits of the relays 8| and 82,which circuits include the normally contacting armature 83 and contact84 of the relay 85. The energizing circuit of the relay 8| also includesthe normally contacting armature 86 and contact 81 of the high-lowpresand 14 to one side of the v aerasac then pulls up its armature 89against the contact 90 and closes the energizing circuit of thecompressor I- At the same time, the relay 82 pulls up its armature 9|against the contact 92 closing the energizing circuit of the outdoor airfan 48.

The heat pump is then in full operation in its cooling cycle, therefrigerant flow being illustrated ig. 4 of the drawing. The compressedrefrigerant vapor from the compressor is cooled in the condenser I4 overwhich the fan 48 moves outdoor air, and is liquefied. The liquidrefrigerant is then expanded through the capillary tubes 30, 31' and 32into the evaporator I which absorbs heat from the indoor air movedthereover by theian 50.

When the thermostat 75 calls for heating, at for example, 72 F. whilethe switch I0 is on its second contact 12, it will close the circuitincluding the contact 93, the relay l4 and the electric mains, causingthe relay T4 to be energized and to pull up its armatures 95 and 96. Thearmature 95 will then strike the contact 91, closing energizing circuitsfor the relays BI and 82, causing the compressor and outdoor air fan tooperate.

At this time, the solenoid 22 is deenergized so that the piston of thereversing valve means 20 rises and routes the refrigerant in the heatingcycle as illustrated by Fig. 3 of the drawing, with the heat exchangerI5 acting as the condenser and the heat exchanger I4 acting as theevaporator.

cult of the relay B9. The low level, indoor thermostat mil completes theenergizing circuit of the relay 99 if the operation of the heat pumpdoes not provide sufficient heating, and the indoor temperature fallsto, for example 68 F., causing the relay 99 to be energized and to pullup its armature I02 against the contact I03 and closing the energizingcircuit of the indoor air heater 44.

While the load is within the capacity of the heat pump, the thermostatI5 will cycle the compressor and outdoor air fan. If the heat loadexceeds the capacity of the heat pump, the thermostat Hit will cycle theindoor heater 44 while the heat pump operates continuously.

If frost forms on the heat exchanger I 6 during the heating cycle, thefrost switch I05 which may be in contact with same, or responsive to apressure drop resulting from frost therein, will strike its contact I66,closing the energizing circult of the solenoid 22, causing the reversingvalve means 2!! to switch from the heating to the cooling cycle, andcausing the heat exchanger I4 to operate as the condenser and to heat upsufliciently to melt the frost, following which, the switch H15 opensand the cooling cycle is changed back to the heating cycle. The outdoorair fan continues in operation at this time since the outdoor air willnormally be at a higher temperature than the heat exchanger I4 whenfrost forms on it Should the outdoor temperature drop to a point atwhich the heat pump cannot supply heat, the outdoor thermostat III! willstrike its The armature 83 will then leave the contact 84 and open thepreviously des ribed energizing circuit of. the. compressor and outdoorair famcausing them to cease operation. Attire tion to electric heatoperation should the outdoor temperature fall too low for heat pumpoperation to be practical, and provides automatic supplementary,electric heat if necessary, during the operation of the heat pump duringthe heatingcycle.

Operation Fig. 10

In the operation of the control system illustrated by Fig. 1 0 of thedrawing, the operator closes the switch I I2 to energize the indoor airindoor thermostat M3 is satisfied within the range of say 72 F. to 78F., the indoor fan alone operates and provides ventilation withoutheating or cooling. If the thermostat I I3 calls for cooling, at say 78F. its armature II-I will strike versing valve means 20 in coolingposition. At the same time, the armature I I1 strikes the contact I20closing the energizing circuit of the relay I2I,

up its armature I23 against the contact I24, closing the energizingcircuits of the compressor I I! and of the outdoor air fan 48.

If the indoor temperature falls to 72 so that the thermostat II3 callsfor heat, its armature H4 first strikes the contact I25 closing theenergizing circuit of the relay I26, causing it to pull up its armaturesI2! and IE3. The armature I28 then strikes the contact I29 closing theenergizing circut of the relay I2I which pulls up its armature I23against the contact I 24 and closing the energizing circuits of thecompressor Hi and of the outdoor fan 48. The solenoid is not energizedat this time so that the reversing valve means 20 is in the heatingposition. At the same time the armature I2! strikes the contact Hi9 andpartially completes the energizing circuit of the relay I32, theenergizing winding of which is connected in series with the armature I55and contact I56 of the relay I35, and is energized when the relay Ipulls down its armature i will be described later.

If the indoor temperature falls to 68 the armature I36 of the thermostatI I3 will strike the contact I31 closing the energizing circuit of therelay I38 causing it to pull up its armature I39 against its contactMlland closing the enersizing circuit ,of'the booster electric in doorheat-- I The. outdoor air thereinstat It Iwhas its annature I42 andcontact I43 connected in series with the energizing winding of the relayE44, and when the outdoor temperature falls below a predeterminedtemperature, which may be 38 the armature I42 strikes the contact i43closing the energizing circuit of the relay I44, the relay armature I33touching its contact I34 at this time. The relay I44 then pulls up itsarmature I 55 against its contact I46, closing the energizing circuit ofthe outdoor air heater 4%, which adds heat to the outdoor air passingover the evaporator and enables the heat pump to work at a highercapacity. This action may be understood by the following example.Without adding heat to the outdoor air passing over the evaporator, theoutdoor air could, for example, enter the evaporator at 40 F., and becooled thereby to 32 F. at an evaporator temperature of 25 If heat isadded to the outdoor air, say 25% of that required, then the outdoor aircould leave the evaporator at 34 F. at an evaporator temperature of 27F. Thus there would be more capacity by a difierence of 2 F. evaporatortemperature. There would be no frost and there would be a coefficient ofperformance greater than one as long as the air leaving the evaporatoris not warmer than the outdoor air.

If the outdoor temperature drops to a still lower predeterminedtemperature which may be 28 F., one at which adding electric heat by theoutdoor air heater 46 loses its value, the stripe-- ture I50 of theoutdoor thermostat l4! strikes the contact [5i completing the energizingcircuit of the relay I35 causing it to pull up its armature I33 awayfrom the contact 534 and to open the energizing circuit of the relay I2!and thereby open the energizing circuits of the compressor and theoutdoor air fan.

At the same time the relay 144 is deenergized, causing the energizingcircuit of the outdoor air heater to be opened.

At the same time the relay I35 pulls down its armature I55 against thecontact I56 and completes the energizing circuit of the relay I32. whichthen pulls up its armature 52 against the contact I53 and closes theenergizing circuit of the indoor air heater 44. The operation of theheater 44 is controlled by the indoor thermostat through the relay I26.

The indoor thermostat will cycle the heat pump during light heatingloads, will cycle the booster indoor heater while continuing theoperation of the heat pump during heavier heat loads, and will cycle thebooster heater during the operation of the main indoor heater when theoutdoor temperature requires that the heat pump be shut down, and theheat from the main indoor heater is insufiicient.

Advantages of the control system of Fig. are that defrosting is nevernecessary since no frost is ever formed; with limited electric heat atthe heat exchanger I4, more B. t. u.s per watt input are obtained whenheating with the heat pump at low outdoor temperatures, and indoorbooster electric heat is always available for providing modulatedheating when either the heat pump or the indoor heater is in operation.

Since the normal position of the reversing valve means 28 is for heatingcycle operation, it will return to this position upon failure of anycomponents which might otherwise result in the continuous operation ofthe heat pump in the cooling cycle, during the heating season. Whilethis might also result, under some conditions, in the operation of theheat pump in the heating cycle during the cooling season, this is farless serious than where the heat pump would operate in the cooling cycleduring the heating season, causing damage to health and freeze-up ofequipment.

Since the heat exchangers I4 and it: are located in vertically extendingracks over the compressor, the space required by the heat pump isreduced, piping is simplified, and drainage of the refrigerant back tothe compressor is expedited. Locating the heat exchanger I5 whichfunctions as the evaporator in the cooling season, directly over theheat exchanger I4 which functions as the condenser at that time, notonly enables condensate to drip on the condenser as previously referredto, but faciltates the connection of ducts to the spaces supplied withconditioned air, since these can be extended over the outdoor air ductas required, without cross-overs. By mounting the indoor and outdoor airfans on the exterior of the rack, they can be placed on either sidethereof for moving the indoor and outdoor air in desired directions.

It should be understood, of course, that the invention is not lirnted tothe exact apparatus and arrangement of apparatus illustrated, sincemodifications thereof may be suggested by those skilled in the artwithout departure from the essence of the invention.

What we claim as our invention, is:

1. In a heat pump having an indoor air heat exchanger, an outdoor airheat exchanger and a refrigerant compressor, the combination ofrefrigerant reversal valve means comprising a cylinder having an inletport connected to the discharge side of said compressor, and having anoppositely disposed outlet port connected to the suction side of saidcompressor, said cylinder having a third port and having a fourth portlocated opposite said third port, said third and fourth ports beinglocated between said inlet and outlet ports, said third port beingconnected to one end of said outdoor air heat exchanger, said fourthport being connected to one end of said indoor air heat exchanger, meansincluding refrigerant expansion means connecting the other ends of saidheat exchangers, a piston slidable in said cylinder from a first to asecond position, said piston having a first transverse slot aligned withsaid inlet and fourth ports when said piston is in said one positionwhereby gas passes from said compressor through said inlet port, saidslot and said fourth port into said one end of said indoor air heatexchanger, said piston having a second transverse slot spacedtransversely of the piston from said first slot and aligned with saidoutlet and third ports when said piston is in said one position wherebygas flows from said one end of said outdoor air heat exchanger throughsaid third port, said second slot and said outlet port to said suctionside of said. compressor, said piston having a third transverse slotspaced longitudinally of the piston from first and second slots, saidpiston having a fourth slot spaced transversely of the piston from saidthird slot, said piston being slidable to said second position wheresaid third slot is aligned with said inlet and third ports and saidfourth slot is aligned with said outlet and fourth ports wherebydischarge gas from said compressor passes through said inlet port, saidthird slot and said third port into said one end of said outdoor airheat exchanger, and gas from said one end of said indoor air heatexchanger passes through said fourth port, said fourth slot and saidoutlet port to said suction side of said compressor, and means formoving said piston to said first position for indoor air heating and tosaid second position for indoor air cooling.

2. The invention claimed in claim 1 in which is the normal position ofthe piston, and in which means is provided for biasing said piston tosaid first position.

3. The invention claimed in claim 2 in which the biasing means is aspring acting against one JOHN L. DITZLER. GERALD L. BIEHN.

Number UNITED STATES PATENTS Name Date Gaugler Sept. 21, 1937 JohnsonOct. 26, 1937 Crago Jan. 10, 1939 Labberton Feb. 21, 1939 Ashley et a1Got. 22, 1940 Horton et a1 Oct. 22, 1940 Gibson May 6, 1941 Hemming eta1. Apr. 21, 1942 Neeson July 7, 1942 Wolfert Feb. 22, 1944 McCloy June13, 1944 Graham Apr. 26, 1949 Pabst Oct. 10, 1950

